“中学生物学教学法”教学改革初探

“中学生物学教学法”教学改革初探夏敏，刘征（南阳师专生物系，４７３０６１）中学生物学教学法是一门实践性很强的应用学科．开设这门课程的主要目的是使学生掌握初中生物学教学法的有关理论和知识，初步具备初中生物学教学能力，从而为学生将来独立从事初中生物学教学...     

基于二次插值的GM(1,1)模型预测方法的改进

从理论上分析了GM(1,1)模型中背景值的计算,指出文[11]利用Newton-Cotes公式构造模型背景值的方法是不可靠的,提出用二次插值构造模型中的背景值,同时用最小二乘法对预测公式中的初值进行改进,并用改进的方法进行了短期预测.其理论分析及仿真结果均表明本文所提出的方法有效可靠,为提高预测精度提供了新的途径.     

江西省普通高等教育与区域经济、科技发展关系的定量研究

实现“江西在中部地区崛起”战略,离不开高等教育、经济和科技的发展。以教育推动经济、科技发展,以经济支撑教育、发展科技,以科技促进教育和经济发展,使三者之间协调互动发展,是加快江西发展的有效之路。通过实证研究,对1999—2009年江西省的普通高等教育现状进行了分析,并利用SPSSl7.0软件对1999—2009年江西高等教育与江西区域经济、区域科技的各项指标进一元回归分析和曲线估计,最后为江西省高等教育与区域经济、区域科技的发展提出对策及建议。     

基于管管相贯的五轴插补算法的研究

针对目前等离子数控切割机进行管管相贯坡口切割过程中,管端相贯数学模型有局限性、插补算法尚不完善等问题,文章通过对各类管管相贯进行分析,提出统一的坡口相贯线数学模型,在该模型的基础上,提出变步长相贯线的五轴插补算法,最后在切割运动方案的基础上,完成机床逆解的理论计算。仿真结果显示,该算法在保证切割效率的前提下,实现了加减速控制,保证加工稳定性,提高切割加工精度。     

新型水驱特征曲线系列(Ⅱ)

针对目前在国内用得比较多的4种水驱特征曲线所存在的问题,提出了一种既简单又综合了甲乙两种类型关系的f _w—R*水驱特征曲线。将丙型与丁型结合提出新的水驱特征曲线,并和经典的水驱特征曲线完全等效的一种水驱特征曲线表达式,同时又能反映含水率-采出程度关系的多条曲线,对它的形状和性质作了一些研究,指出今后水驱特征曲线的研究方向是找出更简单、准确、实用的广义水驱特征曲线。通过实例计算表明,所建立的新型水驱特征曲线与实际数据拟合相关性更强,结果更可靠。     

Doing the Scut Work of Infant Care: Does Religiousness Encourage Father Involvement?

Considerable debate exists regarding whether religiousness promotes or impedes greater father involvement in parenting. Our study addresses this issue using a Midwestern longitudinal dataset that tracks the transition to first parenthood for 169 married couples. We focus on performance of the "messier" tasks of infant care. We find little evidence that religiousness enhances father involvement in this domain. Biblically conservative couples exhibit a greater gender gap in childcare than others, with mothers more involved than fathers. The gender gap is also greater the more fathers work outside the home, the greater mothers' knowledge of infant development, and the more unadaptable the infant. Average daily childcare is lower the greater spouses' work hours, but higher with difficult pregnancies or fussy babies.     

Dynamic Pricing,Production, and Channel Coordination with Stochastic Learning

We consider a decentralized two‐period supply chain in which a manufacturer produces a product with benefits of cost learning, and sells it through a retailer facing a price‐dependent demand. The manufacturer's second‐period production cost declines linearly in the first‐period production, but with a random learning rate. The manufacturer may or may not have the inventory carryover option. We formulate the resulting problems as two‐period Stackelberg games and obtain their feedback equilibrium solutions explicitly. We then examine the impact of mean learning rate and learning rate variability on the pricing strategies of the channel members, on the manufacturer's production decisions, and on the retailer's procurement decisions. We show that as the mean learning rate or the learning rate variability increases, the traditional double marginalization problem becomes more severe, leading to greater efficiency loss in the channel. We obtain revenue sharing contracts that can coordinate the dynamic supply chain. In particular, when the manufacturer may hold inventory, we identify two major drivers for inventory carryover: market growth and learning rate variability. Finally, we demonstrate the robustness of our results by examining a model in which cost learning takes place continuously.     

Life Tables with Covariates: Dynamic Model for Nonlinear Analysis of Longitudinal Data

ABSTRACT

Life table models based on nonlinear dynamics of risk factors are developed using stochastic differential Equations for individual changes and on the resulting Fokker-Planck equation to describe population changes. Central to the model is a microsimulation strategy developed as a numerical procedure to represent a mortality effect when analytic approaches are not applicable. The model is applied to the Framingham Heart Study 46-year follow-up data. Life table functions and projections of risk factors are calculated to demonstrate the nonlinear effects on observable quantities over time. A set of statistically significant nonlinear contributions to covariate dynamics is identified. Their synergistic effect on dynamics and use of them as “new” risk factors are discussed. An important advantage of this approach is the ability to study the effects of health interventions at the individual level. This is illustrated in several examples.     

截面数据精确分段方法研究

针对截面数据分段精度不够,从而导致截面曲线重构精度差的问题,提出一种截面数据精确分段方法。这里重 点研究相邻特征为直线特征和自由特征在满足G1连续时数据的精确分段。首先根据数据平滑的原理及其作用,对被平 滑的数据分别采用不同的领域窗口方法确定出分段点所在的数据点区间;然后以自由曲线的逼近误差作为判断条件,在 该区间内进一步迭代搜索精确的分段点。提出的截面数据分割方法不仅能够在现有数据中寻找分段点,而且可以超越 现有数据点并在其之间寻找更精确的分段点。实例表明,该方法大大提高了截面数据的分段精度,进而使重构的截面曲 线更加符合初始设计意图。     

余价值的分配与账面剩余价值率

在价值转形过程中,由于剩余价值的均衡分配,从不同的利润率出发,可以得到同样的利润率,但并不影响剩余价值率,因为工作日、工人的必要劳动时间和剩余劳动时间在价值转形过程中都没有发生变化。本文提出“账面剩余价值率”的概念,来考察根据资本家的财务报表计算的“剩余价值率”。源于价值转形的“账面剩余价值率”就是“转形账面剩余价值率”;包含资本家在竞争过程中通过各种手段获得的（剩余）价值,由资本主义企业的财务报表中的（息税前）利润量直接计算的账面剩余价值率,就是“竞争账面剩余价值率”。由于剩余价值率是剩余劳动时间与必要劳动时间的比值,因此,可以首先确定所有生产工人的总劳动时间,然后再确定所有生产工人为自己生产的必要劳动时间,进而计算（真正的）总的剩余价值率。随着价值转形过程被垄断所破坏,不同部门的利润率差异被保留甚至扩大,一字曲线就变成了微笑曲线。